Light fixtures currently tend to use light sources with a high lumen, and the light sources are thus provided with high power. The light sources are getting more and more efficient and uses more and more of the supplied energy to generate light; however a considerable part of the power is still generated into heat. For example, arrayed LEDs (light-emitting diode) in a light fixture may have such high power as 500 watts. In this case, it is desired to have a light device with a heat-dissipating system, which works fast and efficiently.
The pending patent US 2005219841 disclosed an illuminating device and projection type video display where three primary colors light sources are provided as a light source. Each light source is a light source in which pluralities of LEDs (light-emitting diodes) are arranged in the same plane surface. The three light sources are arranged on the same plane surface. Furthermore, lines connecting the three light sources form a triangle. Light fluxes (primary optical axes) of each light source are parallel with each other. The three light sources are arranged on one piece of a cooling plate. Further, a wind generator is arranged in such a manner as to be surrounded by said three solid light sources, and air taken in by said wind generator is blown to said cooling plate. Generally, a fan is used in a light device in order to dissipate the heat generated by the light device. However, for the three light sources are arranged on the same plane, the disadvantage of the above illuminating device and projection type video display is the size of the light device is large and the light sources of the device are not movable, thus, the cooling system above-described could not applied in the light fixture with moving head. The space in a moving head is further very limited compared to the Illuminating device and projection type video display of US2005219841, and the electronic circuits for LED control thus are positioned very close to the LEDs, and a further demand on cooling is needed, since the LED control circuits also generate heat.
EP202599 discloses a power LED lighting assembly includes power LEDs (each 1 watt, for example) mounted on a small circuit board of aluminum. To promote air ventilation, the LED circuit board is provided with air openings to communicate with the heat sink. A heat sink enclosure for accommodating the heat sink is also provided with air openings to communicate with the surrounding atmosphere. A micro fan is fixed above the heat sink for forced air ventilation. A temperature sensor is also installed to sense abnormal temperature increases in the assembly to adjust or reduce the intensity of light and protect LEDs against abnormally high temperature. The micro fan is turned on for heat release automatically on a temperature increase. The driver board is housed in a driver box which is separate from the heat sink enclosure. It is in many applications such as in connection with projectors and moving heads impossible to position the driver board in a drive box which is separated from the LED housing.